1. Field of the Invention
This invention relates to a process for inhibiting corrosion of metal surfaces in a closed system which comprises maintaining in said system a composition containing (1) a major amount of an oleaginous vehicle and minor amounts of (2) an oil-soluble hydrophilic cosolvent and (3) the reaction product of substantially equimolar proportions of (a) a dicyclohexylamine and (b) a C.sub.7 organic acid.
2. Description of the Prior Art
The surfaces of metallic components in a closed system are susceptible to corrosion upon standing over a long period of time. For example, in an automotive engine, when not in use for a period of time, as when the same is being transported, the inner surfaces thereof can be corroded because of the condensation of water thereon or, if the engine has previously been operated, because of the acidic corrosion materials produced therein. It is common in shipping or storing many items having metallic parts, such as heat exchangers, pipes, hydraulic cylinders, automotive parts, machine tools, automobile engines, etc., to coat the same with a mineral oil and then wrap the coated item to form a closed container to reduce corrosion. However, in such instances, again water of condensation and/or acidic products in the container will tend to corrode the metallic portions of such items, despite the presence of the mineral oil on the surfaces thereof.
In U.S. Pat. No. 2,784,104, Baseman et. al. wish to displace water from a metal surface by applying corrosion-inhibiting coatings thereon, said coatings comprising a major portion of an oleaginous vehicle and minor amounts of an oil-soluble hydrophilic agent and the reaction product of dicyclohexylamine and octanoic acid.
We have found in the present invention that the susceptibility of a metal surface in a closed system to corrosion in the presence of condensed water or in an atmosphere containing acidic components, for example, from the combustion of a fuel, such as gasoline, can be inhibited or substantially reduced without the need to coat the same with an oleaginous vehicle, such as a mineral oil, by the mere expedient of maintaining in said closed sytem, without need of contacting the metal surface, a composition containing a major amount of an oleaginous vehicle and minor amounts of an oil-soluble hydrophilic cosolvent and the reaction product of substantially equimolar proportions of a dicyclohexylamine and a C.sub.7 organic acid.